Lind, WA, USA
N602GH
AIR TRACTOR INC AT-602
The pilot was conducting an aerial application flight. Surveillance video footage showed that the airplane entered a steep right turn from a straight and level attitude consistent with a course reversal. Shortly thereafter, the airplane entered a steep, nose-down, right-wing-low descent. The airplane subsequently impacted terrain in a nearly flat, upright attitude. A postaccident examination of the airframe and engine did not reveal any mechanical failures that would have precluded normal operation. Flight control continuity was confirmed from the cockpit to all corresponding flight control surfaces. Contact signatures and fractured surfaces from internal components of the engine were consistent with the engine developing power at a high range at the time of impact. Based on the available information, it is likely that the pilot exceeded the airplane’s critical angle of attack during the turn and the airplane entered an aerodynamic stall at an altitude too low for recovery.
On July 2, 2022, about 1733 Pacific daylight time, an Air Tractor AT-602, N602GH, was substantially damaged when it was involved in an accident near Lind, Washington. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 aerial application flight. According to a witness, about 1717, the pilot departed his hangar after refueling and re-loading the hopper for an aerial application flight. GPS data revealed that the pilot was applying pesticide in a west-to-east racetrack pattern (figure 1). While maneuvering at a low altitude over an open field, about 1733, the airplane impacted terrain. Figure 1. GPS data plot of aerial application accident flight Surveillance video footage from a building about 1 nautical mile southwest of the accident site showed that the airplane was flying wings level and transitioned into a steep right turn. About seven seconds later, the airplane entered a nose-down, right--wing-low descent and then disappeared behind a knoll. Shortly after, a plume of dust appears in the video. The airplane impacted a dirt field about 4.5 nautical miles east of the hangar at an elevation of about 1,883 ft mean sea level. The wreckage debris path was about 190 ft long and oriented on a magnetic heading of about 155°. The airplane came to rest upright after it slid upslope (figure 2). Figure 2. View of accident airplane in an open field. The first point of impact was identified as an impression in the ground consistent with the left tire, followed by the left wing and belly of the airplane. The impression contained the left landing gear and fragmented pieces of fiberglass and fuselage. Ground scars and damage to the airplane were consistent with the airplane impacting terrain in a flat, shallow, left-wing-low attitude. There was no evidence of post-impact fire, but an odor consistent with Jet A fuel was present at the site. All major components of the airplane were located within the debris field. The cockpit and forward section of the fuselage sustained impact damage, including the windscreen. The instrument panel sustained forward buckling and compression damage consistent with impact. Multiple gauges from the instrument panel were displaced. The power lever, condition lever, and propeller lever were each found in the full forward position. Flight control continuity was established from the cockpit to each flight control surface, which included the elevator, rudder, and aileron controls. The wings remained attached to the fuselage and exhibited skin buckling consistent with impact damage. The left flap and aileron separated and came to rest forward of the cockpit, while the right flap and aileron remained partially attached to the right wing. Both flaps and ailerons sustained damage consistent with impact. The empennage partially separated and came to rest vertically on the rudder. The leading edges of both elevators, along with the trailing edge of the rudder, sustained compression damage consistent with impact. The engine, a Pratt & Whitney PT6A-65AG, remained attached to its mounts. The reduction gearbox was separated from the engine at the “A” flange. Examination of the engine revealed damage to its internal components consistent with the engine developing power at the time of impact, and damage throughout the second stage carrier slots was consistent with the engine producing power. The engine was equipped with a five-bladed, reversible Hartzell propeller. The hub and blade assembly separated from the reduction gearbox at the propeller flange. The second stage carrier No. 5 bearing journal was fractured consistent with tension overload. Each blade remained attached to the propeller hub and damage sustained was consistent with the engine operating within a high-power range at the time of the accident. Examination of the airframe and engine revealed no evidence of any mechanical malfunctions or anomalies that would have precluded normal operation.
The pilot's exceedance of the airplane's critical angle of attack during a steep turn, which resulted in an aerodynamic stall at an altitude too low for recovery.
Source: NTSB Aviation Accident Database
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